In many ways I prefer debian to ubuntu - and kinda prefer it as a server - however - I always run into the issue of f–king WIFI drivers (as @01101111 mentions above) when I’m installing on a laptop… yeah you can work around this (find the right deb file for non-free and put it on yet ANOTHER USB thumb drive [i.e. other than the one you’re installing from!] - or - plug it into ethernet) - but it’s still a PITA - and Ubuntu doesn’t make you do that…
Also - that book when opened as an epub in Cosmic Cuttlefish - looks awful (using Cosmic’s default epub viewer) - I had to install Calibre to view it properly…